Temperature measuring apparatus



June 18, l. R. L. FEARN 2,204,797

TEMPERATURE MEASURING APPARATUS Original Filed Jan. 19, 1939 Richard L.Hzarn I/VVf/V TOR.

E L %ILA A it orne qs.

Patented June 18, 1940 UNITD STATES YPATENT OFFlCE 2,204,797 TEMPERATUREMEASURING APPARATUS ()rlginal application January 19, 1939, Serial No.

Divided and this application 2, 1939, Serial No. 287,984

August 1 Claim. (01. 73-341 This invention relates to improvements intemperature measuring apparatus and is particularly adapted to themeasurement of the temperature of a heated, rapidly moving strand, suchas a copper wire.

The objects and advantages of this invention will be apparent from thefollowing description when taken in connection with the attacheddrawing.

This invention resides substantially in the combination, construction,arrangement, and relative location of parts, all in accordance with thisdisclosure.

This invention is particularly adapted for use with but not limited touse with apparatus of the type disclosed in my co-pending applicationSerial No. 251,759, filed January 19, 1939, of which this is adivisional application.

In the accompanying drawing,

Figure 1 is a longitudinal, vertical, central, cross-sectional Viewthrough a portion of an apparatus employing this invention; and

Figure 2 is a circuit diagram of connections thereof.

In the heat treatment of metallic strands which are moving at highspeeds in the direction of their length, it is often desirable, but atthe same time extremely difficult, to accurately measure the temperaturethereof. Where, as in the case of the method, for example, of the parentapplication of which this is a division, it is desired to know quiteaccurately the temperature of a heated, rapidly moving strand, no othersatisfactory method or apparatus is known to me for the purpose. As isapparent from the above, the purpose of this invention is to provide anaccurate temperature measuring mechanism for providing either directly areading of the actual temperature of the heated strand takencontinuously while it is moving or to provide an indication of thevariation of the temperature thereof from a desired value.

In the drawing, a portion of the apparatus disclosed in the parentapplication is illustrated. It is shown as comprising a casing 50, ofany suitable material and preferably heat insulated, which has a smallaperture at the left hand end thereof through which the wire W enters asit moves axially. Mounted on the end of the housing is a heavy metalplate 5i having a flaring aperture in alignment with the aperture in thewall of the housing through which the strand may enter thereinto. Thefunction of the plate 5| is of no concern to the invention hereindisclosed. Mounted in the housing and spaced from binding posts (notshown) mounted on the terthe left hand end wall thereof is a barrier orwall 60 which substantially divides the housing into two compartments.This wall is provided with an aperture in which one end of an innerglass housing 6| is supported and provided with an 5 apertured closuremember through which the wire may move into the glass chamber. Thischamber likewise is of no importance to the present invention.

In one of the compartments thus formed by m the housing and wall ismounted a support 53 which extends through the upper wall of the housingboth interiorly and exteriorly thereof. The lower end, that is, the endwithin the compartment, is provided with a pair of projecting guides 54which have aligned passages therethrough with ends flaring outwardlytowards the direction from which the strand W comes. The apertures inthe guides 54 are in alignment with the aperture in the end of thehousing and the 0 passage into the chamber 6|. Thus the strand W maymove in a straight line from the heating apparatus at the left, notshown, and while still heated move through the compartment and into theinner chamber 6|. Supported between the guides 54 is a short metallictube 55 which has a central passage therethrough slightly larger thanthe external diameter of the strand W. Mounted on the support 53 is athermocouple 56 which is welded to the metallic tube 55 so as not onlyto support it in the position shown but also to be in heat conductiverelation therewith. The leads for this thermocouple extend upwardly ofthe support 53, as indicated at A, and terminate on suitable minal board58. A second thermocouple 51 projects down into the compartment so as tobe exposed to the heat therein and is provided with a pair of leads Bwhich likewise go to suitable binding posts (not shown) on the terminalboard 58.

The connections for this arrangement are illustrated in Figure 2. Thethermocouples 56 and 51 are connected in opposition, that is, so thatthe currents flowing therefrom, if of equal value, nullify each other.One of the leads A and one of the leads B are connected together tosecure this result, while the other leads A and B are connected asindicated at C to the indicating meter 59, which may, for example, be amillivolt meter, as indicated by the reference characters M. V. At H isdiagrammatically illustrated any suitable form of heating mechanism,such as an electric heater, provided with the current supply leads 12for connection to any suitable source. The heater H is provided to aidin maintaining a desired temperature within the chamber 50 including thethermocouple compartment.

With this apparatus in operation and properly adjusted,the'thermocouples being connected in series opposition and with thethermocouples at the same temperature, the currents generated by themare equal and opposed so that a null, reading is secured on themilli-volt meter 59. Thermocouple 56 is directly subject to the temperature of the heated strand Wpassing through the metallic tube 55,While the thermocouple 51 is directly subject to the temperature in thechamber or compartment. With everything in balance and the apparatusproperly adjusted, a

null reading will continue. However, if the tem--- perature of the WireW moving through the metallic tube should rise or fall, a differentialcurrent will flow to the meter 59, which may be calibrated in a numberof different ways to give for example, the normal desired temperature ofthe strand is 300 C. and the apparatus is in a state of balance andproperly adjusted to give a null reading, then any rise or fall in thetemperature of'the wire will be directly reflected on the meter 59,which may be calibrated to indicate an increase or decrease oftemperature with respect to the desired temperature of 300 C.

Itis, of course, apparent that the heating element ii and the heatsupplied to the thermocouple chamber from the heated wire and by whatother external sources as may be employed,

will cause asubstantially fixed temperature in the thermocouplecompartment when the apparatus is running properly and is in a state ofequilibrium.

Other ways of calibrating and using this equip- 1 ment-will be apparentto those skilled in the art, .and I do not, therefore,,deeire to belimited to the disclosure as given for purposes of illustration butrather to the scope of the appended claim.

What I claim is:

A'device for measuring the temperature of a moving heated strandcomprising a housing through which the strand moves axially and whichheats the'atmosphere within the housing, a heat conducting tube in saidhousing through which the strand moves, a thermocouple in contact withsaid tube, a second thermocouple spaced from said tube and exposed tothe atmosphere in said housing, an indicating device, and circuitconnections for connecting said thermocouples in series opposition toeach other and to said indicating device.

RICHARD L. FEARN.

